CQI Interleaver Layout for Unequal Error Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wireless communication systems face inefficiencies in reducing the overhead of Channel Quality Indicator (CQI) feedback in uplink communications, particularly in orthogonal frequency division multiple access (OFDMA) systems, due to the need for reliable transmission of varying importance levels of CQI information bits.
Innovation Solution
The proposed method involves an interleaver design that provides unequal error protection to CQI information bits based on their importance, allocating more protection to critical bits such as ACK/NAK, wideband CQI, and rank feedback, while less protection to less significant bits, using specific bit mapping and interleaving schemes for single transmit antenna and MIMO spatial multiplexing systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If equal error protection is provided to all CQI information bits, then the transmission reliability is uniformly maintained, but the overhead increases and critical information does not receive sufficient protection
Solution Approach 1:
The patent applies local quality by providing different levels of error protection to different portions of CQI information bits based on their importance. Critical bits (ACK/NAK, wideband CQI, rank feedback) are placed in positions that receive stronger protection through the interleaving scheme, while less critical bits receive standard protection. This resolves the contradiction by ensuring critical information gets sufficient protection without uniformly increasing overhead for all bits.
2Reliability
If more error protection is provided to critical CQI bits, then the reliability of critical information transmission is improved, but the complexity of the interleaver design increases
Solution Approach 1:
The patent segments CQI information bits into different categories based on their importance: critical bits (ACK/NAK, wideband CQI, rank feedback) and less critical bits. The interleaver is designed to map these segmented bits to different positions in the transmitted sequence, with critical bits placed in positions that experience lower error rates. This segmentation approach allows differential protection without requiring a completely complex custom interleaver design.
Solution Approach 2:
The patent applies preliminary action by pre-determining the mapping of CQI bits to interleaver positions based on their importance before transmission. The interleaver pattern is designed in advance to place critical bits in protected positions, eliminating the need for real-time complex decisions during transmission. This pre-planned mapping reduces the operational complexity while maintaining reliable protection of critical information.
3Ease of manufacture
If all CQI bits are transmitted with the same protection level, then the implementation is simple, but the bit error rate of critical information cannot be sufficiently reduced
Solution Approach 1:
The patent implements local quality by applying different error protection strategies to different portions of the CQI data stream. Critical bits are mapped to specific positions in the interleaved sequence that correspond to more reliable transmission resources, while less critical bits are mapped to positions with standard protection. This approach maintains relative implementation simplicity while significantly reducing the bit error rate of critical CQI information through the unequal error protection provided by the position-based mapping.
Data Source
AI summary
For transmission of a block of control information within a wireless network, the control information is interleaved to form an ordered set of control bits, wherein more important information bits of the control information are placed into a first portion of the ordered set of control bits, with less important information bits of the control information placed into a second portion of the ordered set of controls bits. The ordered set of control bits is encoded to form an encoded block of data. The encoded block of data is transmitted to a serving base station, wherein bits from the first portion of the ordered set of control bits will statistically have a lower bit error rate (BER) than bits from the second portion of the ordered set of control bits during transmission.